Citation Note: These data were collected as part of a research study published in Environmental Science and Technology. Please reference the following paper when citing these data. Blondes, M.S., Shelton, J.L., Engle, M.A., Trembly, J.P., Doolan, C.A., Jubb, A.M., Chenault, J.M., Rowan, E.L., Haefner, R.J., and Mailot, B.E., 2020, Utica Shale Play Oil and Gas Brines: Geochemistry and Factors Influencing Wastewater Management: Environmental Science & Technology, https://dx.doi.org/10.1021/acs.est.0c02461. The Utica and Marcellus Shale Plays in the Appalachian Basin are the 4th and 1st largest natural gas producing plays in the United States. Hydrocarbon production generates large volumes of brine (“produced water”) that must be disposed of, treated, or reused. Though Marcellus brines have been studied extensively, there are few studies from the Utica Shale Play. This study presents new brine chemical analyses from 16 Utica Shale Play wells in Ohio and Pennsylvania. Results from Na-Cl-Br systematics and stable and radiogenic isotopes suggest that the Utica Shale Play brines are likely residual pore water concentrated beyond halite saturation during the formation of the Ordovician Beekmantown evaporative sequence. The narrow range of chemistry for the Utica Shale Play produced waters (e.g., total dissolved solides = 214 – 283 g/L) over both time and space implies a consistent composition for disposal and reuse planning. The amount of salt produced annually from the Utica Shale Play is equivalent to 3.4% of annual U.S. halite production. Utica Shale Play brines have radium activities 580 times the EPA maximum contaminant level and are supersaturated with respect to barite, indicating the potential for surface and aqueous radium hazards if not properly disposed of.